The assessment of proper and effective ventilatory function in premature newborns suffering from respiratory distress secondary to surfactant deficiency is difficult, and only crude measures are currently available. In part this arises from the delicate and fragile nature of the premature infant, and the life threatening conditions in which they live due to excessively high lung recoil, in turn secondary to immature Type II pneumocytes and surfactant deficiency. Sufficiently high airway pressures necessary to ventilate these babies are near levels associated with barotrauma that can itself be highly detrimental and compromise survival risk. The ability to monitor collapsed and atelectatic lung regions, and their response in reopening of units with titration of ventilatory strategies, is essential to improvement of medical care and the ultimate endpoint of the survival of healthy infants as well as minimal damage inflicted on the pulmonary structures during mechanical ventilation. To this end, we propose the development of a "ventilation stethoscope" (VS), designed for use in the Neonatal Intensive Care Unit (NICU), to measure regional ventilation. The VS is based on two key components. First, is the use of hyperpolarized noble gases for the assessment of ventilation and second, is the recent development of magnet designs that allow MRI in a region that is projected externally or remotely from the position of the current wires or permanent magnet that produce the magnetic field. Our specific aims include designing and fabricating a portable magnet (~0.1T) and radio frequency components of the system and then demonstrating the ability of the VS to detect inhomogeneous regional ventilation in rabbits that have been challenged with dysfunctional surfactant. In addition, we will develop and test quantitative methods to measure absolute regional ventilation. This proposal responds to Challenge Topic 06-HL-111: Develop devices and instruments for assessing and supporting assessment of pulmonary function in an ICU. PUBLIC HEALTH RELEVANCE: Ventilator Induced Lung Injury is a common cause of complications and sometimes death in critically ill patients with respiratory failure. At present, there are no devices available to measure regional ventilation in the ICU. We propose to build a portable magnetic resonance device that will allow noninvasive measurement of regional ventilation in the neonatal intensive care unit, where most patients require mechanical ventilation. The utility of this device will be to allow clinicians to optimally adjust ventilator settings to allow ventilation but to avoid lung injury.